Complete Measurement of Polarization-Transfer Observables for the ReactionC12(p,p′

Abstract

The first complete measurement of the polarization-transfer observables in the (p $ p') reaction at intermediate energies is reported. Data are presented for the reaction i2 C(p,p') 12 C to the 1 + , T = 0 (12.71-MeV) and 1 + , T = l (15.11-MeV) states at 500 MeV for laboratory scattering angles of 3.5°, 5.5°, 7.5°, and 12.0°. Linear combinations of these observables are shown to exhibit a very selective dependence on the isoscalar and isovector spin-dependent components of the nucleon-nucleon interaction.

Relations between measured and calculated spin observables in inelastic scattering of polarized protons for excitation of the 1+, T = 0 state in 12C

“…The same levels were excited in ( ) scattering at Е р = 500 MeV in two experiments [14,15]. The result was a complete set of measurements obtained for the transfer of spin for the excitation of the levels noted above, 1 + .…”

“…In full experiments [14], three types of polarized beams of protons are used: (1) a beam polarized in the direction perpendicular to the scattering plane (type N), (2) a beam polarized along the direction of motion of the accelerated particles (type L), and (3) a beam polarized in the scattering plane but in a direc tion orthogonal to the axis of motion of the particles (type S). The following notation is then introduced for the indices of the spin observables D ij : (i, j) = N, L, S. The spin transfer (or polarization transfer) coeffi cients D ij , in which i = j, are referred to as diagonal, since the observables D NN , D LL , and D SS are diagonal elements of the general matrix form, representing a set of relations among all polarization characteristics of incident and scattered protons [18,37].…”

“…As was already noted, the NN scattering amplitude must be expressed in terms of certain quantities that are invariant with respect to spatial rotations, spatial reflections, and time reversal, and are charge inde [40] at 0° for 0.4 GeV, by solid [15] and open [14] dots for 0.5 GeV, and by triangles [38] pendent and also meet other requirements. The simi lar scattering amplitude M(q) in a two body center of mass system was constructed and calculated as a func tion of spin and isospin [42].…”

“…The relativistic interpretation of the structure of the nuclear related condition has the nonzero spin difference function (P-A y ) in this for malism being shaped in the most natural way without the inclusion of exchange processes [12,13]. However, the accuracy of the descriptions of a number of spin observables in the inelastic scattering of polarized pro tons at the energies Е р = 500 MeV for the excitation of 1 + , Т = 0 in 12 C [14] using the relativistic approach proved to be very poor [13].…”

Nuclear spin and isospin excitations

“…A promising tool for resolving experimentally the different multipolarities is the (p,n) spin-flip transfer reaction (Taddeucci et al, 1984(Taddeucci et al, , 1986Watson et al, 1986Watson et al, , 1987Taddeucci, 1987) which, in principle, is sensitive to different J w values (Cornelius et al, 1981;Seestrom-Morris et al, 1982;McClelland et al, 1984), as we shall discuss in Sec. VI.…”